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Abstract:

An electronic camera comprises an image generation unit that generates a
plurality of images for red-eye detection based upon an image obtained by
capturing an image of a subject with an image-capturing element, a
setting unit that sets a specific mode among a plurality of modes related
to electronic camera functions, a selection unit that selects a specific
type of red-eye detection processing among a plurality of types of
red-eye detection processing different from one another, based upon the
mode set via the setting unit; and a red-eye detection unit that detects
a red-eye area based upon the images for red-eye detection by executing
the red-eye detection processing selected by the selection unit.

Claims:

1. An electronic camera, comprising: an image generation unit that
generates a plurality of images for red-eye detection based upon an image
obtained by capturing an image of a subject with an image-capturing
element, the plurality of images for red-eye detection being different
from one another with respect to numbers of pixels; a setting unit that
sets a specific mode among a plurality of modes related to electronic
camera functions; a selection unit that selects a specific type of
red-eye detection processing among a plurality of types of red-eye
detection processing different from one another, based upon the mode set
via the setting unit, different images for red-eye detection being used
in different types of red-eye detection processing respectively; and a
red-eye detection unit that detects a red-eye area based upon the image
for red-eye detection by executing the red-eye detection processing
selected by the selection unit.

Description:

RELATED APPLICATION

[0001] This is a Continuation of application No. 13/137,691 filed Sep. 2,
2011, which is a continuation of application Ser. No. 11/703,242 filed
Feb. 7, 2007, the disclosure of which is incorporated herein in its
entirety.

INCORPORATION BY REFERENCE

[0002] The disclosures of the following priority applications are herein
incorporated by reference:

[0006] The present invention relates to a red-eye correction function of a
camera equipped with an electronic flash unit.

[0007] 2. Description of Related Art

[0008] There are cameras known in the related art that execute red-eye
detection processing by referencing a captured image. Japanese Laid Open
Patent Publication No. 2005-167697 discloses a technology whereby the
length of processing time is reduced by reducing the size of a captured
image and executing red-eye detection processing on the reduced image.

SUMMARY OF THE INVENTION

[0009] However, there is a problem in that since a single red-eye
detection processing method is adopted regardless of whether the camera
is engaged in a single-shot photographing operation or a continuous
shooting operation, the red-eye detection and correction processing
cannot be executed over the time period depending on the particular
photographing conditions.

[0010] According to the first aspect of this invention, an electronic
camera comprises an image generation unit that generates a plurality of
red-eye detection images based upon an image obtained by capturing an
image of a subject with an image-capturing element, a setting unit that
sets a specific mode among a plurality of modes related to electronic
camera functions, a selection unit that selects a specific type of
red-eye detection processing among a plurality of types of red-eye
detection processing different from one another, based upon the mode set
via the setting unit; and a red-eye detection unit that detects a red-eye
area based upon the red-eye detection image by executing the red-eye
detection processing selected by the selection unit.

[0011] According to the second aspect of the invention, in the electronic
camera according to the first aspect of the invention, it is preferred
that different red-eye detection images are used in the different types
of red-eye detection processing respectively.

[0012] According to the third aspect of the invention, in the electronic
camera according to the second aspect of the invention, it is preferred
that the plurality of red-eye detection images are different from one
another with respect to levels of image accuracy.

[0013] According to the fourth aspect of the invention, in the electronic
camera according to the second aspect of the invention, it is preferred
that the plurality of red-eye detection images are constituted with
different numbers of pixels respectively.

[0014] According to the fifth aspect of the invention, in the electronic
camera according to any of the first through the fourth aspect of the
invention, it is preferred that in one type of red-eye detection
processing among the plurality of types of red-eye detection processing
which are different from one another, red-eye detection is executed by
using one red-eye detection image, whereas in another type of red-eye
detection processing, red-eye detection is executed by using two red-eye
detection images each different from the one red-eye detection image.

[0015] According to the sixth aspect of the invention, in the electronic
camera according to any of the first through the forth aspect of the
invention, it is preferred that the plurality of modes include a
photographing mode and a reproduction mode; and the red-eye detection
unit detects a red-eye area through first red-eye detection processing
when the reproduction mode has been selected and detects a red-eye area
through second red-eye detection processing when the photographing mode
has been selected.

[0016] According to the seventh aspect of the invention, in the electronic
camera according to the first aspect of the invention, it is preferred
that the plurality of modes include a high-speed continuous shooting mode
and a low-speed continuous shooting mode; and the red-eye detection unit
detects a red-eye area through first red-eye detection processing when
the low-speed continuous shooting mode has been selected and detects a
red-eye area through second red-eye detection processing when the
high-speed continuous shooting mode has been selected.

[0017] According to the eighth aspect of the invention, in the electronic
camera according to the sixth or the seventh aspect of the invention, it
is preferred that the image generation unit generates a first red-eye
detection image with a superior image accuracy level and a second red-eye
detection image with a lower level of image accuracy based upon the image
obtained by capturing an image of the subject with the image-capturing
element; and first red-eye detection image is used to detect the red-eye
area the first red-eye detection processing, and the first and the second
red-eye detection images are used to detect the red-eye area through the
second red-eye detection processing.

[0018] According to the ninth aspect of the invention, in the electronic
camera according to the eighth aspect of the invention, it is preferred
that if a red-eye area cannot be detected in the second red-eye detection
image, the first red-eye detection image is used to detect a red-eye area
during the second red-eye detection processing.

[0019] According to the tenth aspect of the invention, in the electronic
camera according to any of the sixth through the ninth aspect of the
invention, it is preferred that limits are imposed with regard to lengths
of processing time over which the plurality of types of red-eye detection
processing different from one another are executed, and the limited
length of processing time set for the second red-eye detection processing
is smaller than the limited length of processing time set for the first
red-eye detection processing.

[0020] According to the eleventh aspect of the invention, in the
electronic camera according to the first aspect of the invention, it is
preferred that the plurality of modes include a high-speed continuous
shooting mode, a low-speed continuous shooting mode and a reproduction
mode, the selection unit selects first red-eye detection processing when
the high-speed continuous shooting mode has been selected via the setting
unit, selects second red-eye detection processing when the low-speed
continuous shooting mode has been selected via the setting unit and
selects third red-eye detection processing when the reproduction mode has
been selected via the setting unit; and the red-eye detection unit
detects a red-eye area based upon the red-eye detection image by
executing the red-eye detection processing having been selected by the
selection unit.

[0021] According to the twelfth aspect of the invention, in the electronic
camera according to the eleventh aspect of the invention, it is preferred
that the image generation unit generates a first red-eye detection image
with a lowest level of image accuracy, a second red-eye detection image
ranging over a focus-match area in the captured image, which has a
highest level of image accuracy, and a third red-eye detection image with
an image accuracy level between the image accuracy levels of the first
and the second red-eye detection image, all based upon the image obtained
by capturing an image of the subject with the image-capturing element,
the first red-eye detection image is used to detect the red-eye area
through the first red-eye detection processing, the first and the second
red-eye detection images are used to detect the red-eye area through the
second red-eye detection processing; and the third and the second red-eye
detection images are used to detect the red-eye area through the third
red-eye detection processing.

[0022] According to the thirteenth aspect of the invention, in the
electronic camera according to the twelfth aspect of the invention, it is
preferred that the second red-eye detection image is used to detect a
red-eye area if a red-eye area cannot be detected in the first red-eye
detection image during the second red-eye detection processing; and the
second red-eye detection image is used to detect a red-eye area if a
red-eye area cannot be detected in the third red-eye detection image
during the third red-eye detection processing.

[0023] According to the fourteenth aspect of the invention, in the
electronic camera according to the twelfth or the thirteenth aspect of
the invention, it is preferred that the first red-eye detection image is
a display image generated by reducing an image for recording, which is
obtained by capturing an image of the subject with the image-capturing
element, and the third red-eye detection image is a red-eye detection
image obtained by reducing the image for recording.

[0024] According to the fifteenth aspect of the invention, in the
electronic camera according to any of the eleventh through the fourteenth
aspect of the invention, it is preferred that limits are imposed with
regard to length of processing time over which the first red-eye
detection processing and the second red-eye detection processing are
executed and the limited length of processing time set for the first
red-eye detection processing is smaller than the limited length of
processing time set for the second red-eye detection processing.

[0025] According to the sixteenth aspect of the invention, in the
electronic camera according to any of the first through the fifteenth
aspect of the invention, it is preferred that the red-eye detection unit
includes a red-eye position detection unit that detects a position at
which red-eye occurs based upon the red-eye detection images; and the
electronic camera further comprises a processing unit that executes
red-eye correction processing on the captured image based upon the
position of the red-eye detected by the red-eye position detection unit.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026]FIG. 1 illustrates the essential structure adopted in an electronic
still camera achieved in an embodiment of the present invention;

[0027]FIG. 2 is a block diagram of the control system in the electronic
still camera achieved in the embodiment of the present invention;

[0035] The following is an explanation of a single lens reflex electronic
camera with a red-eye correction function achieved in an embodiment of
the present invention, given in reference to drawings. FIG. 1 shows the
essential structure adopted in the camera according to the present
invention, which comprises a camera body 100, a viewfinder device 120A, a
shutter release button 213 operated to issue a photographing instruction
and a photographic lens 130. The photographic lens 130, which includes
lenses 131a˜131c and an aperture 132, is detachably mounted at the
camera body 100. The lens group 131b constitutes a focal point adjustment
lens which is driven by a lens drive motor 133.

[0036] Subject light enters the camera body 100 after passing through the
photographic lens 130 and prior to a full press operation of the shutter
release button 213, the subject light having entered the camera body 100
is reflected at a quick return mirror 111 and forms an image at a
viewfinder screen 120. The subject image is guided from a pentaprism 121
through a relay lens 122 to an eyepiece lens 123 and also the subject
image at the pentaprism 121 is reformed via a photometering image
reforming lens 124 onto the light receiving surface of a photometering
element 125 constituted with an SPD, a CCD or the like. The brightness
distribution of the subject undergoes photoelectric conversion at the
photometering element 125.

[0037] In addition, prior to the full press operation of the shutter
release button 123, the subject light having been transmitted through a
semi-transmissive area of the quick return mirror 111 is reflected along
the downward direction at a sub mirror 112 and thus enters a focal point
detection device 113. The focal point detection device 113 may be, for
instance, a phase-difference focal point detection device of the known
art. In response to the full press operation of the shutter release
button 213, the quick return mirror 111 swings upward and the subject
light forms an image on an image-capturing element such as a CCD 202 via
a shutter (not shown). The image-capturing element may be constituted
with a photoelectric conversion element other than a CCD, such as a CMOS.

[0038] As shown in the block diagram in FIG. 2, analog image signals read
out from the CCD 202 in response to a drive signal provided from a CCD
driver 203 undergo signal amplification, black level adjustment and the
like at a pre-process circuit 204. The analog image signals are then
converted to digital image signals at an A/D converter 205 and the
digital image signals resulting from the conversion are input to an ASIC
207. The ASIC 207 executes image processing such as γ correction
and white balance adjustment on the digital image signals input thereto
and outputs the digital image signals having undergone the image
processing as image data. The image data are displayed at a color monitor
211 after the photographing operation and also are recorded into a memory
209 and a detachable non-volatile recording medium 208.

[0039] A mode selector switch 212 is operated to select a photographing
mode, a reproduction mode, a setup mode or the like as the operating mode
of the electronic camera. A high-speed continuous shooting mode, a
low-speed continuous shooting mode, a single-shot photographing mode or
the like can be selected as the photographing mode in which a
photographing operation is executed in response to an operation of the
shutter release button 213. In the reproduction mode, a CPU 210 reads out
image data recorded in the recording medium 208 and displays a reproduced
image generated by using the image data at the color monitor 211. In the
setup mode, menu setting and the like are performed and red-eye
correction processing, too, is set in the setup mode. A flash unit on/off
switch 214 outputs an operation signal for allowing or disallowing light
emission at the electronic flash unit 206 to the CPU 210.

[0040] The CPU 210 includes a red-eye detection unit 210a and a red-eye
correction unit 210b as its functional units. The red-eye detection unit
210a, to which red-eye detection image data generated at the ASIC 207 are
input, detects positional coordinates of an area where red-eye has
occurred based upon the image data input thereto. The positional
coordinate detection may be executed by using hue information, saturation
information, brightness information or the like of the known art. Based
upon the positional coordinates of the red-eye area detected via the
red-eye detection unit 210a, the red-eye correction unit 210b corrects
the red-eye portion of the photographic image data. The correction
processing should be executed through a method of the known art by, for
instance, substituting a color read from the surrounding area for the
red-eye portion of the image data or by masking the red-eye area with a
specific color, so as to ensure that the red-eye portion in the image
data is rendered to be natural-looking.

[0041] The red-eye detection images generated at the ASIC 207 are
explained in reference to FIG. 3. FIG. 3A shows a main image 401. The
main image 401 is generated by, for instance, executing white balance
processing and the like on image signals output by the CCD 202 upon
capturing an image. In the photographing mode, the main image 401 is
obtained based upon image data having been JPEG-compressed and
temporarily stored in the memory 209 or based upon image data having been
JPEG-compressed and recorded in the recording medium 208. Alternatively,
an image obtained based upon raw data may be used as the main image.
While the data size of the main image may be, for instance,
2592×1944 dots, the main image may assume a data size other than
this. An area 402 enclosed by the dotted lines in the main image 401 is a
focus-match area and hereafter, the image within this area is to be
referred to as a focus-match area image 402. Since a focus match is often
achieved around the face of a person in an image the main photographic
subject of which is a person, the red-eye detection unit 210a uses this
focus-match area image 402 for detection of the positional coordinates of
the red-eye area, as well as a reduced red-eye detection image 403 to be
detailed later.

[0042]FIG. 3B shows the reduced red-eye detection image 403, the data
size of which is smaller than that of the main image 401. The reduced
red-eye detection image 403 is generated by the ASIC 207 through reducing
processing combined with interpolation processing instead of simple
reducing processing, so as to ensure that information indicating the
color component corresponding to the red-eye area in the main image 401
does not become lost through the reduction processing. It is to be noted
that while the data size of the reduced red-eye detection image 403 may
be, for instance, 1024×768 dots, the reduced red-eye detection
image may assume a data size other than this. However, the number of
pixels constituting the reduced red-eye detection image should be smaller
than the number of pixels constituting the focus-match area image 402. As
described later, the reduced red-eye detection image 403 is used by the
red-eye detection unit 210a for red-eye detection in the reproduction
mode.

[0043]FIG. 3C shows a reduced display image 404. The reduced display
image 404, generated by the ASIC 207, is displayed at the color monitor
211 in the reproduction mode. The reduced display image 404 is a VGA
(video graphics array) image assuming a data size equivalent to
640×480 dots. The number of pixels constituting the reduced display
image 404 is smaller than the number of pixels constituting the reduced
red-eye detection image 403. As explained later, the reduced display
image 404 is used by the red-eye detection unit 210a for red-eye
detection in the high speed continuous shooting mode and the low-speed
continuous shooting mode. As described above, the focus-match area image
402, the reduced red-eye detection image 403 and the reduced display
image 404 are all used as red-eye detection images.

[0044] The images to be used by the red-eye detection unit 210a in the
red-eye detection processing among the plurality of types of red-eye
detection images described above are determined in correspondence to a
specific mode among various photographing modes and the reproduction mode
selected via the mode selector switch 212.

[0045] When the high-speed continuous shooting mode has been selected, the
red-eye detection unit 210a executes red-eye detection by using the
reduced display image 404. The processing executed by using the reduced
display image is to be referred to as simplified red-eye correction
processing. The operational flow of the simplified red-eye correction
processing is shown in FIG. 4A. Image signals having been accumulated in
the CCD 202 are read out under the imaging control and then the ASIC 207
generates the reduced display image 404 through the image processing.
During the red-eye detection, the red-eye detection unit 210a detects the
positional coordinates of the red-eye area by using the reduced display
image 404. In the red-eye correction, the red-eye correction unit 210b
converts the positional coordinates of the red-eye area having been
detected through the red-eye detection to coordinates in the main image
401, executes the correction processing in the main image 401 as
explained earlier, JPEG compresses the main image 401 and records the
compressed main image.

[0046] The CPU 210 sets the total length of processing time per frame to
200 msec for the simplified red-eye correction processing. 50 msec is
allocated as the processing time for each of the various phases of the
processing, i.e., the imaging control, the image processing, the red-eye
detection and the red-eye correction, while processing a single image
frame. The length of time elapsing during the red-eye detection is
counted with a timer, and if the positional coordinates of a red-eye area
are not detected within the allocated 50 msec period, the red-eye
detection unit 210a interrupts the detection and the red-eye correction
unit 210b does not execute the red-eye correction processing. Then, the
CPU 210 waits in standby until the total length of processing time, i.e.,
200 msec, elapses, before photographing an image for the next frame. It
is to be noted that the total length of processing time per frame does
not need to be 200 msec and that the length of processing time allocated
to each phase of the processing may be other than 50 msec.

[0047] When the low-speed continuous shooting mode or the single-shot
photographing mode has been selected, the red-eye detection unit 210a
executes red-eye detection by using the focus-match area image 402 and
the reduced display image 404. The processing executed by using the
focus-match area image 402 and the reduced display image 404 is to be
referred to as standard red-eye correction processing. The operational
flow of the standard red-eye correction processing is shown in FIG. 43.
While the contents of the various phases of processing are similar to
those of the simplified red-eye correction processing explained earlier,
the ASIC 207 generates the focus-match area image 402 and the reduced
display image 404 based upon the main image 401 having been captured.

[0048] In the red-eye detection, the red-eye detection unit 210a detects
the positional coordinates of a red-eye area as explained earlier by
using the reduced display image 404. The red-eye detection unit 210a also
detects the positional coordinates of the red-eye area by using the
focus-match area image 402. Then, the red-eye detection unit 210a
compares the red-eye area positional coordinates detected in the reduced
display image 404 with the red-eye area positional coordinates detected
in the focus-match area image 402 and makes a decision as to whether or
not the two sets of red-eye area positional coordinates match each other.
If the two sets of red-eye area positional coordinates match, the red-eye
correction unit 210b executes the red-eye correction processing in the
main image 401 based upon the red-eye area positional coordinates having
been detected.

[0049] If the two sets of red-eye area positional coordinates do not
match, the red-eye detection unit 210a detects the positional coordinates
of a red-eye area by using one of surrounding area images 405 set around
the focus-match area image 402. Then, the red-eye detection unit 210a
makes a decision as to whether or not the red-eye area positional
coordinates detected in the surrounding area image 405 match the red-eye
area positional coordinates detected in the reduced display image 404.
FIG. 9 shows the positional relationships between the surrounding area
images 405 and the focus-match area image 402. The specific surrounding
area image 405 to be used by the red-eye detection unit 210a for the
positional coordinate detection should be selected by switching from one
surrounding area image to another in the order indicated by the numerals
assigned to the individual surrounding area images 405 in FIG. 9.

[0050] Since the processing does not need to be executed in the low-speed
continuous shooting mode or the single-shot photographing mode as fast as
in the high-speed continuous shooting mode, the CPU 210 sets the total
length of processing time per frame to 250 msec. While processing the
single frame, 50 msec is allocated to each of the following phases of the
processing; imaging control, image processing and red-eye correction and
100 msec is allocated to the red-eye detection. As in the simplified
red-eye correction processing, the length of time elapsing during the
red-eye detection is counted with a timer. If the positional coordinates
of a red-eye area are still not detected after the allocated 100 msec
period elapses, the red-eye detection unit 210a interrupts the detection
and the red-eye correction unit 210b does not execute the red-eye
correction processing. Then, the CPU 210 waits in standby until the total
length of processing time, i.e., 250 msec, elapses, as in the simplified
red-eye correction processing. It is to be noted that the total length of
processing time per frame does not need to be 250 msec and that the
lengths of time allocated to the various processing phases and the
red-eye detection may be other than 50 msec and 100 msec.

[0051] When the reproduction mode has been selected, the red-eye detection
unit 210a executes red-eye detection by using the focus-match area image
402 and the reduced red-eye detection image 403. The processing executed
by using the focus-match area image and the reduced red-eye detection
image is to be referred to as high accuracy red-eye correction
processing. FIG. 4C shows the operational flow of the high accuracy
red-eye correction processing. Based upon image data read out from the
recording medium 208 through the read processing, the ASIC 207 generates
the focus-match area image 402 and the reduced red-eye detection image
403 as in the simplified red-eye correction processing and the standard
red-eye correction processing explained earlier. Unlike in the simplified
red-eye correction processing or the standard red-eye correction
processing, the CPU 210 does not set a specific length of processing time
per frame in the high accuracy red-eye correction processing. Namely, the
red-eye detection unit 210a continuously executes the processing until
the red-eye area is detected. In addition, if the red-eye area positional
coordinates detected in the focus-match area image 402 and the red-eye
area positional coordinates detected in the reduced red-eye detection
image 403 do not match, the red-eye detection unit 210a detects the
red-eye area positional coordinates by using one of the surrounding area
images 405 set around the focus-match area image 402, as in the standard
red-eye correction processing.

[0052] The procedures through which the three types of correction
processing are executed are explained next.

[0053] --Simplified Red-Eye Correction Processing--

[0054] In reference to the flowchart presented in FIG. 5, the red-eye
correction processing executed for an image photographed by the
electronic camera set in the high-speed continuous shooting mode, i.e.,
the simplified red-eye correction processing, is explained. It is to be
noted that the flowchart presented in FIG. 5 shows the procedure of the
processing executed in conformance to a program executed by the CPU 210
in the electronic camera. The program, which is stored in the memory (not
shown), is started up when the red-eye correction processing, the light
emission at the electronic flash unit 206 and the high-speed continuous
shooting mode are selected as photographing conditions.

[0055] In step S101, a decision is made as to whether or not the shutter
release button 213 has been pressed down. If an affirmative decision is
made, i.e., if it is decided that the shutter release button 213 has been
depressed, the operation proceeds to step S102. If, on the other hand, a
negative decision is made, i.e., if it is decided that the shutter
release button 213 has not been depressed, the operation waits in standby
until the shutter release button 213 is operated.

[0056] In step S102, image signals are read out from the CCD 202 via the
CCD driver 203. Once the image signals having been read out are input to
the ASIC 207, the operation proceeds to step S103. In step S103, an image
generation processing instruction is issued to the ASIC 207. The ASIC 207
generates the main image 401 and the reduced display image 404 created
based upon the main image 401 in response to the instruction. Once these
images are generated, the operation proceeds to step S104.

[0057] In step S104, the image data of the main image 401 and the reduced
display image 404 having been generated by the ASIC 207 are stored into
the memory 209. Upon storing the image data of the two images, the
operation proceeds to step S105. In step S105, detection of the
positional coordinates of an area where a red-eye phenomenon has
manifested in the reduced display image 404 is started, before the
operation proceeds to step S106. It is to be noted that as the red-eye
area positional coordinate detection starts, the timer is started up to
start counting the length of time elapsing while the positional
coordinate detection is in progress.

[0058] In step S106, a decision is made as to whether or not red-eye area
positional coordinates have been detected. If an affirmative decision is
made, i.e., if it is decided that the positional coordinates of a red-eye
area have been detected, the operation proceeds to step S107. If, on the
other hand, a negative decision is made, i.e., if it is decided that the
positional coordinates of a red-eye area have not been detected, the
operation proceeds to step S112.

[0059] In step S107, a decision is made as to whether or not the timer
count value provided by the timer having started the time count in step
S105, i.e., the length of time having elapsed while the red-eye area
positional coordinate detection has been in progress, is equal to or
greater than the predetermined length of time, 50 msec. If an affirmative
decision is made, i.e., if it is decided that the red-eye area positional
coordinate detection has been in progress for 50 msec or more, the
red-eye area positional coordinate detection is interrupted and the
operation skips to step S110 without executing the red-eye correction
processing for the main image 401. If a negative decision is made in step
S107, i.e., if it is decided that the length of time having elapsed while
the red-eye area positional coordinate detection has been in progress is
less than 50 msec, the operation proceeds to step S108. It is to be noted
that once the decision-making in step S107 ends, the time count by the
timer having been started in step S105 is stopped and the timer count
value is reset to 0.

[0060] In step S108, the positional coordinates of the red-eye area in the
main image 401 are calculated based upon the red-eye area positional
coordinates detected in the reduced display image 404. Namely, since the
number of pixels constituting the main image 401 is 2592×1944 dots
and the number of pixels constituting the reduced display image 404 is
640×480 dots, the red-eye area coordinates detected in the reduced
display image 404 are multiplied by 4.05 along the vertical and
horizontal directions to determine the red-eye area positional
coordinates in the main image 401. Once the red-eye area positional
coordinates in the main image 401 are calculated, the operation proceeds
to step S109.

[0061] In step S109, the red-eye correction processing is executed for the
main image 401 and then the operation proceeds to step S110. In the
red-eye correction processing, the red-eye area at the positional
coordinates having been calculated in step S108 in the image data of the
main image 401 stored in the memory 209 is corrected. The red-eye
correction is executed by substituting a color read from the surrounding
area for the red-eye portion of the image data or a specific color, as
described earlier.

[0062] If, on the other hand, no red-eye area is detected through the
red-eye area positional coordinate detection processing having been
started in step S105 and a negative decision is made in step S106
accordingly, a decision is made in step S112 as to whether or not the
timer count value at the timer having started the time count in step S105
indicates a value equal to or greater than 50 msec. If an affirmative
decision is made, i.e., if it is decided that the red-eye area positional
coordinate detection has been in progress for 50 msec or more, the
red-eye area positional coordinate detection is interrupted and the
operation skips to step S110 without executing the red-eye correction
processing for the main image 401. In addition, the timer having been
started in step S105 is stopped at this point and the timer count value
is reset to 0. If a negative decision is made in step S112, i.e., if it
is decided that the length of time having elapsed while the red-eye area
positional coordinate detection has been in progress is less than 50
msec, the operation returns to step S105 to start the red-eye area
positional coordinate detection again.

[0063] In step S110, the image data of the main image 401 having been
temporarily stored into the memory 209 are JPEG-compressed, and then the
operation proceeds to step S111. In step S111, the image data of the main
image 401, having undergone the compression processing, are recorded into
the recording medium 208.

[0064] --Standard Red-Eye Correction Processing--

[0065] In reference to the flowchart presented in FIG. 6, the red-eye
correction processing executed when the electronic camera is set in the
low-speed continuous shooting mode or the single-shot photographing mode,
i.e., the standard red-eye correction processing, is explained. As does
the flowchart of the simplified red-eye correction processing, the
flowchart presented in FIG. 6 shows the procedure of processing executed
in conformance to a program executed by the CPU 210 in the electronic
camera. The program, which is stored in the memory (not shown), is
started up as the red-eye correction processing, light emission at the
electronic flash unit 206 and the low-speed continuous shooting mode or
the single-shot photographing mode are selected. In addition, the same
step numbers are assigned to steps in which processing similar to that in
the flowchart presented in FIG. 5 is executed and the following
explanation focuses on differences from the procedure shown in the
flowchart presented in FIG. 5.

[0066] In step S203, an image generation processing instruction is issued
to the ASIC 207. The ASIC 207 generates the focus-match area image 402
and the reduced display image 404 created based upon the main image 401,
as well as the main image 401 itself, in response to the instruction.
Once these images are generated, the operation proceeds to step S204.

[0067] In step S204, the image data of the main image 401, the focus-match
area image 402 and the reduced display image 404 having been generated by
the ASIC 207 are stored into the memory 209. Upon storing these image
data, the operation proceeds to step S205. In step S205, detection of the
positional coordinates of an area where a red-eye phenomenon has
manifested in the reduced display image 404 is started, before the
operation proceeds to step S206. It is to be noted that as the red-eye
area positional coordinate detection starts, the timer is started up to
start counting the length of time elapsing while the positional
coordinate detection is in progress.

[0068] In step S206, a decision is made as to whether or not red-eye area
positional coordinates have been detected. If an affirmative decision is
made, i.e., if it is decided that the positional coordinates of a red-eye
area have been detected, the operation proceeds to step S207. If, on the
other hand, a negative decision is made, i.e., if it is decided that the
positional coordinates of a red-eye area have not been detected, the
operation proceeds to step S211.

[0069] In step S207, the positional coordinates of an area in which the
red-eye phenomenon has manifested in the focus-match area image 402 are
detected and the operation proceeds to step S208. In step S208, a
decision is made as to whether or not the red-eye area positional
coordinates having been detected in the reduced display image 404 in step
S206 match the red-eye area positional coordinates having been detected
in the focus-match area image 402 in step S207. If an affirmative
decision is made, i.e., if it is decided that the two sets of red-eye
area positional coordinates match, the operation proceeds to step S209.
If a negative decision is made, i.e., if it is decided that the two sets
of red-eye area positional coordinates do not match, the operation
proceeds to step S214.

[0070] If no red-eye positional coordinates are detected and a negative
decision is made in step S206, a decision is made in step S211 as to
whether or not the timer count value at the timer having started the time
count in step 205 indicates a value equal to or greater than 100 msec. If
an affirmative decision is made, i.e., if it is decided that 100 msec or
more has elapsed, the red-eye area positional coordinate detection is
interrupted and the operation skips to step S110 after stopping the timer
having been started in step S205 and resetting the timer count value to
0, without executing the red-eye correction processing. If, on the other
hand, a negative decision is made, i.e., if it is decided that the 100
msec period has not elapsed, the operation proceeds to step S212.

[0071] In step S212, red-eye area positional coordinate detection is
executed based upon the focus-match area image 402 and then the operation
proceeds to step S213. In step S213, a decision is made as to whether or
not red-eye area positional coordinates have been detected. If an
affirmative decision is made, i.e., if it is decided that the positional
coordinates of a red-eye area have been detected, the operation proceeds
to step S209. If, on the other hand, a negative decision is made, i.e.,
if it is decided that the positional coordinates of a red-eye area have
not been detected, the operation returns to step S211.

[0072] If the two sets of red-eye area positional coordinates do not match
and a negative decision is made in step S208 accordingly, a decision is
made in step S214 as to whether or not the timer count value provided by
the timer having started the time count in step S205, is equal to or
greater than the predetermined length of time, 100 msec. If an
affirmative decision is made, i.e., if it is decided that 100 msec or
more has elapsed, the operation skips to step S110 after stopping the
timer having been started in step S205 and resetting the timer count
value to 0. If a negative decision is made in step S214, i.e., if it is
decided that the length of time having elapsed while the red-eye area
positional coordinate detection has been in progress is less than 100
msec, the operation proceeds to step S215.

[0073] In step S215, one of the surrounding area images 405 set around the
focus-match area image 402 is selected to be used for the red-eye area
positional coordinate detection. A specific surrounding area image may be
selected by switching from one surrounding area image to another in a
specific predetermined order indicated by, for instance, the numbers
assigned to the individual surrounding area images 405 in FIG. 9. Once
the processing in step S215 is competed, the operation proceeds to step
S216.

[0074] In step S216, the positional coordinates of an area in which a
red-eye phenomenon has manifested in the surrounding area image 405 are
detected, and then the operation returns to step S208 to make a decision
as to whether or not the red-eye area coordinates in the reduced display
image 404 and the red-eye coordinates in the surrounding area image 405
match.

[0075] In step S209, a decision is made as to whether or not the timer
count value provided by the timer having been started in step S205
indicates a value equal to or greater than the predetermined length of
time 100 msec. If an affirmative decision is made, i.e., if it is decided
that 100 msec or more has elapsed, the operation skips to step S110. If,
on the other hand, a negative decision is made, i.e., if it is decided
that the 100 msec period has not elapsed, the operation proceeds to step
S210. It is to be noted that once the decision-making in step S209 ends,
the time count on the timer having been started in step S205 is stopped
and the timer count value is reset to 0.

[0076] In step S210, the positional coordinates of the red-eye area in the
main image 401 are calculated based upon the red-eye area positional
coordinates detected in one of; the focus-match area image 402, the
reduced display image 404 and the surrounding area image 405. Namely, the
positional coordinates in the main image 401 are calculated as follows
based upon the red-eye area positional coordinates detected in the
reduced display image 404. Since the number of pixels constituting the
main image 401 is 2592×1944 dots and the number of pixels
constituting the reduced display image 404 is 640×480 dots, the
red-eye area coordinates detected in the reduced display image 404 are
multiplied by 4.05 along the vertical and horizontal directions to
determine the positional coordinates of the red-eye area in the main
image 401. The positional coordinates of the red-eye area in the main
image are calculated as follows based upon the red-eye area positional
coordinates detected in the focus-match area image 402 or the surrounding
area image 405. Since the focus-match area image 402 and the surrounding
area image 405 are each an image cut out from the main image 401, the
red-eye area positional coordinates in the focus-match area image 402 or
the surrounding area image 405 only need to be correlated to coordinates
within the corresponding area in the main image 401. Once the red-eye
area positional coordinates in the main image 401 are calculated, the
operation proceeds to step S109.

[0077] --High Accuracy Red-Eye Correction Processing--

[0078] In reference to the flowchart presented in FIG. 7, the red-eye
correction processing executed when the electronic camera is set in the
reproduction mode, i.e., the high accuracy red-eye correction processing,
is explained. The flowchart presented in FIG. 7 shows the procedure of
processing executed in conformance to a program executed by the CPU 210
in the electronic camera. The program, which is stored in the memory,
(not shown) is started up as the reproduction mode is selected. In
addition, the same step numbers are assigned to steps in which processing
similar to that in the flowchart presented in FIG. 5 is executed and the
following explanation focuses on differences from the procedure shown in
the flowchart presented in FIG. 5.

[0079] In step S301, the image data of the main image 401 recorded in the
recording medium 208 are read out and are stored into the memory 209,
before the operation proceeds to step S302. In step S302, an instruction
for generating the focus-match area image 402 and the reduced red-eye
detection image 403 based upon the image data of the main image 401
having been stored into the memory 209 is issued to the ASIC 207. Once
the images are generated, the operation proceeds to step S303. It is
assumed that information specifying the focus-match area is written in
the image data of the main image 401 recorded in the recording medium
208.

[0080] In step S303, the image data of the focus-match area image 402 and
the reduced red-eye detection image 403 are stored into the memory 209
and then the operation proceeds to step S304. In step S304, detection of
the positional coordinates of an area where a red-eye phenomenon has
manifested in the reduced red-eye detection image 403 is started and then
the operation proceeds to step S305.

[0081] In step S305, a decision is made as to whether or not red-eye area
positional coordinates have been detected. If an affirmative decision is
made, i.e., if it is decided that the positional coordinates of a red-eye
area have been detected, the operation proceeds to step S306. If, on the
other hand, a negative decision is made, i.e., if it is decided that the
positional coordinates of a red-eye area have not been detected, the
operation proceeds to step S308.

[0082] In step S306, the positional coordinates of an area in which a
red-eye phenomenon has manifested in the focus-match area image 402 are
detected and the operation proceeds to step S307. In step S307, a
decision is made as to whether or not the red-eye area positional
coordinates having been detected in the reduced red-eye detection image
403 in step S304 match the red-eye area positional coordinates having
been detected in the focus-match area image 402 in step S306. If an
affirmative decision is made, i.e., if it is decided that the two sets of
red-eye area positional coordinates match, the operation proceeds to step
S310. If a negative decision is made, i.e., if it is decided that the two
sets of red-eye area positional coordinates do not match, the operation
proceeds to step S311.

[0083] If, on the other hand, no red-eye area positional coordinates are
detected in the reduced red-eye detection image 403 and a negative
decision is made in step S305 accordingly, red-eye area positional
coordinate detection is executed by using the focus-match area image 402
in step S308, and then the operation proceeds to step S309. In step S309,
a decision is made as to whether or not red-eye area positional
coordinates have been detected. If an affirmative decision is made, i.e.,
if it is decided that the positional coordinates of a red-eye area have
been detected, the operation proceeds to step S310. If, on the other
hand, a negative decision is made, i.e., if it is decided that the
positional coordinates of a red-eye area have not been detected, the
operation proceeds to step S314.

[0084] If the red-eye area positional coordinates in the reduced red-eye
detection image 403 and the red-eye area positional coordinates in the
focus-match area image 402 do not match and a negative decision is made
in step S307 accordingly, a decision is made as to whether or not the
red-eye area positional coordinates detection has been performed in all
the surrounding area images 405 as shown in FIG. 9 in step S311. If an
affirmation decision is made, i.e., if it is decided that the red-eye
area positional coordinates detection has been performed in all the
surrounding area images 405, the operation proceeds to step S110. If a
negative decision is made, i.e., if it is decided that there is the
surrounding area image 405 in which the red-eye area positional detection
has not been performed, the operation proceeds to step S312. If there is
the surrounding area image 405 in which the red-eye area positional
detection has not been performed and a negative decision is made in step
S311 accordingly, the image used for the red-eye area positional
coordinate detection is switched to one of the surrounding area images
405 set around the focus-match area image 402 in step S312. A specific
surrounding area image 405 is selected in the predetermined order, as
explained earlier. Once the processing in step S312 is completed, the
operation proceeds to step S313.

[0085] In step S313, the positional coordinates of an area where a red-eye
phenomenon has manifested in the surrounding area image 405 are detected
and then, the operation returns to step S307 to make a decision again as
to whether or not the red-eye area coordinates in the reduced red-eye
detection image 403 and in the surrounding area image 405 match.

[0086] If no red-eye area positional coordinates are detected in the
focus-match area image 402 and a negative decision is made in step S309
accordingly, the operation proceeds to step S314. The processing executed
from step S314 (judgment of the red-eye detection processing in all the
surrounding images) through step S316 (detecting red-eye area positional
coordinates in the surrounding area image) are identical to those
executed from step S311 (judgment of the red-eye detection processing in
all the surrounding images) through step S313 (detecting red-eye area
positional coordinates in the surrounding area image) respectively.

[0087] In step S310, the positional coordinates of the red-eye area in the
main image 401 are calculated based upon the red-eye area positional
coordinates detected in the focus-match area image 402, the reduced
red-eye detection image 403 or the surrounding area image 405. Namely,
the positional coordinates in the main image 401 are calculated as
follows based upon the red-eye area positional coordinates detected in
the reduced red-eye detection image 403. Since the number of pixels
constituting the main image 401 is 2592×1944 dots and the number of
pixels constituting the reduced red-eye detection image 403 is
1024×768 dots, the red-eye area coordinates detected in the reduced
red-eye detection image 403 are multiplied by 2.53125 along the vertical
and horizontal directions to determine the positional coordinates of the
red-eye area in the main image 401. The positional coordinates of the
red-eye area in the main image are calculated as follows based upon the
red-eye area positional coordinates detected in the focus-match area
image 402 or the surrounding area image 405. Since the focus-match area
image 402 and the surrounding area image 405 are each an image sliced out
from the main image 401, the red-eye area positional coordinates in the
focus-match area image 402 or the surrounding area image 405 only need to
be correlated to coordinates within the corresponding area in the main
image 401. Once the red-eye area positional coordinates in the main image
401 are calculated, the operation proceeds to step S109 to execute the
red-eye correction processing described earlier.

[0088] The following advantages are achieved in the embodiment described
above.

(1) In correspondence to the specific current mode selected from a
plurality of modes having been selected in the electronic camera, one
type of processing among the simplified red-eye correction processing,
the standard red-eye correction processing and the high accuracy a
red-eye correction processing is selected and the red-eye detection is
executed accordingly. Consequently, the red-eye area can be detected
without compromising the accuracy, regardless of the mode having been
selected in the electronic camera. (2) Different types of red-eye
detection processing are executed when the high-speed continuous shooting
mode is selected as the photographing mode and when the low-speed
continuous shooting mode or the single-shot photographing mode is
selected as the photographing mode. Namely, in the high-speed continuous
shooting mode, which requires high-speed processing, the simplified
red-eye correction processing is executed, whereas the standard red-eye
correction processing is executed in the low-speed continuous shooting
mode and the single-shot photographing mode in which the processing does
not need to be executed as fast as in the high-speed continuous shooting
mode. As a result, red-eye correction can be completed within the optimal
length of processing time, without compromising the red-eye detection
accuracy. (3) In the simplified red-eye correction processing, the
red-eye detection unit 210a executes the red-eye detection by using the
reduced display image 404 generated through reducing processing of the
data constituting the main image 401. As a result, since the red-eye area
positional coordinates are detected by using the reduced display image
404 constituted with a smaller number of pixels compared to the main
image 401, the processing can be executed at high-speed as required in
the high-speed continuous shooting mode. (4) In the standard red-eye
correction processing, the red-eye detection unit 210 executes the
red-eye detection by using the focus-match area image 402 sliced cut out
from the main image 401 and the reduced display image 404 generated
through reducing processing of the data constituting the main unit 401.
Namely, the red-eye area positional coordinate detection is first
executed by using the reduced display image 404 constituted with a
smaller number of pixels, and if no red-eye area coordinates are
detected, the red-eye area positional coordinate detection is executed by
using the focus-match area image 402 constituted with a larger number of
pixels. As a result, the processing speed required in the low-speed
continuous shooting mode or the single-shot photographing mode can be
achieved without compromising the red-eye detection accuracy. (5) If the
red-eye detection unit 210a detects a red-eye area in the reduced display
image 404 during the standard red-eye correction processing, the accuracy
of the red-eye area positional coordinates having been detected is
verified by using the focus-match area image 402 constituted with a
greater number of pixels. Thus, the desired level of red-eye detection
accuracy is assured since the red-eye correction processing is never
executed on, for instance, lips erroneously recognized as a red-eye area.
(6) When the high-speed continuous shooting mode, the low-speed
continuous shooting mode or the single-shot photographing mode has been
selected in the camera, the red-eye detection processing by the red-eye
detection unit 210a is interrupted after the red-eye detection processing
has been in progress equal to or longer than a predetermined length of
time. In addition, different settings are selected for the predetermined
length of time in the simplified red-eye correction processing and in the
standard red-eye correction processing. This means that since the red-eye
correction processing is not executed indefinitely, and the photographing
operation for the next frame is not delayed significantly, a good
photographing opportunity does not need to be missed. (7) When the
reproduction mode has been selected in the camera, the high accuracy
red-eye correction processing is executed. In the high accuracy red-eye
correction processing, the red-eye detection unit 210a detects red-eye
area positional coordinates by using the focus-match area image 402
sliced out from the main image 401 and the reduced red-eye detection
image 403 generated through reducing processing of the image data
constituting the main image 401. Since the reduced red-eye detection
image 403 is constituted with a greater number of pixels than the reduced
display image 404, a higher level of red-eye detection accuracy is
assured. (8) No limits are imposed with regard to the length of red-eye
detection processing time in the high accuracy red-eye correction
processing. This means that any red-eye phenomenon can be detected with a
high level of accuracy in the reproduction mode.

[0089] The embodiment described above allows for the following variations.

(1) In the simplified red-eye correction processing and the standard
red-eye correction processing, the red-eye correction is executed for the
main image 401 and the image processing is executed to generate image
data for recording, only after the detection of red-eye area positional
coordinates in the entire image area of the focus-match area image 402 or
the reduced display image 404 is completed. However, the detection of
red-eye area positional coordinates in the focus-match area image 402 or
the reduced display image 404 and the image processing for generating the
portion of the main image 401 to be recorded, which corresponds to the
image area having been scanned, may be executed concurrently, as shown in
FIG. 8. By concurrently executing the positional coordinate detection and
the image processing, a greater length of time can be allocated to the
red-eye area positional coordinate detection. Alternatively, the length
of time allocated to the red-eye detection may remain unaltered and, in
this case, the total length of processing time per frame can be reduced.
(2) While the time count for the length of time over which the red-eye
detection processing remains in progress is started as the red-eye
detection processing starts in the simplified red-eye correction
processing and the standard red-eye correction processing in the
explanation provided above, the time count may instead be started at the
start of the imaging control. In the latter case, the predetermined
length of time should be set in correspondence to the length of time to
elapse between the imaging control start and the red-eye detection
processing end and a decision with regard to a timeout should be made
based upon this length of time. (3) In the simplified red-eye correction
processing and the standard red-eye correction processing, a time count
may be executed for each of the various phases of processing, i.e., the
imaging control, the image processing, the red-eye detection and the
red-eye correction, and a decision with regard to a timeout may be made
based upon a predetermined length of time set in correspondence to each
processing phase. In such a case, each phase of processing can be
interrupted if its processing time exceeds the corresponding length of
time set for the particular processing phase. (4) While an explanation is
given above in reference to the embodiment on an example in which the
focus-match area image 402 and the reduced display image 404 are used in
the standard red-eye correction processing, the reduced red-eye detection
image 403 and the reduced display image 404 may be used in the standard
red-eye correction processing, instead. (5) Different red-eye detection
images or different red-eye detection processing methods may be used in
the continuous shooting modes and in the reproduction mode. For instance,
simplified red-eye correction processing may be executed by using the
reduced display image 404 in the continuous shooting modes, whereas
standard red-eye correction processing may be executed by using the
reduced display image 404 and the focus-match area image 402 as red-eye
detection images in the reproduction mode. Alternatively, simplified
red-eye correction processing may be executed by using the reduced
red-eye detection image 403 in the continuous shooting modes. (6)
Different red-eye detection images or different red-eye detection
processing methods may be used in the continuous shooting modes and in
the single-shot photographing mode. For instance, simplified red-eye
correction processing may be executed by using the reduced display image
404 in the continuous shooting modes, whereas standard red-eye correction
processing may be executed by using the reduced display image 404 and the
focus-match area image 402 as red-eye detection images in the single-shot
photographing mode. Alternatively, the reduced red-eye detection image
403 may be used in the continuous shooting modes, whereas standard
red-eye correction processing may be executed in the single-shot
photographing mode by using the reduced red-eye detection image 403 and
the focus-match area image 402 as red-eye detection images. (7) Different
red-eye detection images or different red-eye detection processing
methods may be used in the single-shot photographing mode and in the
reproduction mode. For instance, simplified red-eye correction processing
may be executed in the single-shot photographing mode by using the
reduced display image 404, whereas high accuracy red-eye correction
processing may be executed in the reproduction mode by using the reduced
display image 404 and focus-match area image 402 as red-eye detection
images or high accuracy red-eye correction processing may be executed in
the reproduction mode by using the reduced red-eye detection image 403
and the focus-match area image 404 as red-eye detection images.
Alternatively, standard red-eye correction processing may be executed in
the single-shot photographing mode by using the reduced red-eye detection
image 403 and the focus-match area image 402. It is to be noted that
different red-eye detection images or different red-eye detection methods
may be used in the photographing modes, which includes the single-shot
photographing mode and the continuous shooting modes, and in the
reproduction mode.

[0090] In various modes including the low-speed continuous shooting mode
and the reproduction mode, at least two types of red-eye detection images
with varying levels of image accuracy may be generated and if a red-eye
area cannot be detected in the red-eye detection image with the lower
level of image accuracy, red-eye detection may be executed by using the
red-eye detection image with the higher or superior level of image
accuracy so as to assure reliable red-eye detection.

(8) The focus-match area image 402 is used in the standard red-eye
correction processing and the high accuracy red-eye correction processing
in the expression provided above. Instead, a small image area in the main
image 401, which corresponds to the red-eye area positional coordinates
detected in the reduced display image 404 or the reduced red-eye
detection image 403, may be used in place of the focus-match area image
402 for the red-eye detection.

[0091] While an explanation is given above in reference to the embodiment
on an example in which the present invention is adopted in a camera that
allows the use of exchangeable lenses, the present invention may be
adopted in a camera with an integrated lens.

[0092] The above described embodiments are examples and various
modifications can be made without departing from the spirit and scope of
the invention.

Patent applications by Masaki Hayashi, Chiba-Shi JP

Patent applications by NIKON CORPORATION

Patent applications in class Including noise or undesired signal reduction

Patent applications in all subclasses Including noise or undesired signal reduction